add BAMFK-4 (#17985)

* add BAMFK-4

keyboards/keebio/bamfk4/keymaps/default/keymap.c

@@ -0,0 +1,18 @@
+// Copyright 2021 Danny Nguyen (@nooges)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include QMK_KEYBOARD_H
+
+// Defines names for use in layer keycodes and the keymap
+enum layer_names {
+    _MAIN,
+};
+
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+    [_MAIN] = LAYOUT(
+        KC_A,
+        KC_B,
+        KC_C,
+        KC_D
+    )
+};